Exploring the Relationship Between Trunk-Pelvic Coordination and Pitching Velocity in Baseball Pitchers

Shiu-Min Wang, Wei-Li Hsu, Jyh-How Huang, Yuh-Renn Wu
Purpose:

This study aimed to investigate the association between trunk-pelvic coordination and pitching velocity in baseball pitchers.

Methods:

Baseball pitchers aged 18 to 25 with no history of surgery were recruited. Four inertial measurement units (IMUs) were attached to the pitching arm, the stride leg thigh, the sternum, and the pelvis during the pitching motion. Each pitcher threw 10 maximal-effort fastballs. The IMUs recorded pelvic and trunk rotation angles, with the thigh IMU detecting foot contact (FC) and the pitching arm IMU detecting maximal external rotation (MER) and maximal internal rotation (MIR).

Coordination was assessed using angle-angle plots to represent the relationship between pelvic and trunk rotation during two pitching periods. The first period was from FC to MER, and the second was from MER to MIR. Coupling angles ranged from 0 to 360 degrees and were categorized into two patterns: in-phase (both joints rotating in the same direction) and anti-phase (joints rotating in opposite directions). The percentage of in-phase and anti-phase coordination was calculated for both periods. Spearman’s correlation was used to assess the relationship between coordination patterns and pitching velocity, with a p-value 0.05 indicating statistical significance.


Results:

Twelve baseball pitchers were recruited (age: 18.25 ± 2.05 years; height: 180.41 ± 4.33 cm; weight: 82.16 ± 9.28 kg). A significant positive correlation was found between anti-phase coordination and pitching velocity from FC to MER (r = 0.77, p 0.01). Additionally, in-phase coordination from MER to MIR was positively correlated with pitching velocity (r = 0.85, p 0.01).

Conclusion(s):

Pitchers who demonstrated higher percentages of anti-phase coordination from FC to MER and in-phase coordination from MER to MIR achieved greater pitching velocity. These findings suggest that specific coordination patterns may enhance performance and could be incorporated into training programs to improve pitching velocity and reduce injury risks.

Implications:

This study provides valuable evidence that optimizing trunk-pelvic coordination is critical for improving pitching velocity. Pitchers can use these findings to develop targeted training programs aimed at enhancing these coordination patterns, potentially leading to improved performance and reduced injury risk.

Funding acknowledgements:
This work was supported by Ministry of Science and Technology (NSTC 113-2425-H-028-002) awarded to Dr. Wei-Li Hsu.
Keywords:
baseball
coordination
pitching velocity
Primary topic:
Sport and sports injuries
Did this work require ethics approval?:
Yes
Name the institution and ethics committee that approved your work:
The Ethics Committee of National Taiwan University Hospital
Provide the ethics approval number:
202210101RIND
Has any of this material been/due to be published or presented at another national or international conference prior to the World Physiotherapy Congress 2025?:
No

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